Dental impression band



June 30, 1931. w P, LACE 1,812,008

DENTAL IMPRESSI ON BAND Filed Dec. 19, 1929 gwuento'o (1am nu Patented June 30, 1931 UNITED STATES WILLIAM r. LACE, or DENVER, COLORADO DENTAL IMPRESSION BAND Application filed December 19,1929.. Serial No. 415,336.

This invention relates to an impression band for use in dentistry. The usual dental impression band comprises a short metallic cylinder of any suitable, soft, non-corrosive metal. The bands are generally employed for obtaining impressions of the cavity which has been prepared for an inlay so that a model of the tooth can be obtained for use in the laboratory. The usual dental impression bands have been very unsatisfactory and impractical because there is absolutely nothing upon the bands to provide a finger grip to facilitate their removal. The impression compound hardens into the cavity and into the undercut exterior surfaces of the tooth, making it an exceedingly difficult operation to lift the band after the impression compound has hardened. It is, at times, necessary to employ two fingers of each hand in order to obtain suflicient grip and the struggle to lift the band causes distortion in the impression which makes it impossible to form a perfectly fitting inlay in the laboratory. This struggle to remove the band i is exceedingly distressing to the patient and often when great effort is put upon the band to remove it, it will suddenly snap from place so that the tightly gripped fingers will force the sides inwardly and break the thin edges of the delicate impression surfaces.

The principal object of this invention is to provide an impression band with a finger gripping projection adjacent one of its extremities so that a firm grip can be obtained thereon between the thumb and fingers of one hand which will allow the band to be easily lifted from the place without crushing or distortion.

The straight sharp edge of the usual im pression band often cut-s or scratches the thumb of the operator when he is endeavoring to force the impression. compound therein.

Another object of this invention is to pro vide an-impression band which will not injure the thumb of the operator and which will act as a -funnel to compress and direct the compound against the tooth.

A-further obj ect of the invention is to pro vide an impression band, the lower portion :6 of which, can be shaped toconform tothe outli'neof any desired tooth without distort: ing or constricting the top thereof so that there will be no interference with the forelngof the impression compound against the tooth. l I

A still further object is to provide animQ pression band of larger area adjacent its outer extremity so that the impression compound cannotbe drawn from the band by its adherance to the tooth.

Other objects and advantages reside in the detailconstruction of the invention, which is designed for simplicity, economy, and efliciency. Thesewill become more apparent from the following description.

In the followingfdetailed description of the invention reference is had to the accompanying drawings which forms apart here-.

of. Like numerals refer to like parts in all views of the drawings. and throughout the description.

In the drawings: v Fig. l is a perspective view illustrating the preferred form ofthe improved dental impression band.

Fig. 2 illustrates in usew.

Fig. 3 is an end View of theband illusthe improved dental band trating how the operating extremity may be distorted without constricting the gripping extremity. I

The use of an impression band is'well known in. the dental profession-and will be but briefly outlined here. The cavity in the tooth is prepared in theusual way such as indicated at 10 in the tooth 11' of Fig. 2."

The band is then partially filled with 'impression compound, such as indicated at 14, which has been previously softened by heating and is forced onto the tooth with the thumb closing the outer extremity thereof. Considerable pressure is applied to force the impresison compound to fiow into and conform to the contour of the tooth and cavity. The compound is then allowed to cool and the band is lifted from the tooth. \Ve now have within the band a perfect impression of the tooth and cavity which can be filled with amalgam or similar modeling substance to obtain a perfect model of the tooth. The inlay can then. be built up to-fit this model tooth with the'assurance that it will also fit the natural tooth when placed thereon, provided the impression was not disturbed or damaged during the removal of the band.

This improved dental band is illustrated at 12. In its preferred form,.one extremity of the band 12 is turned outwardly entirely,

around its periphery to form a-slightly-bel'lshaped extremity 13. The bell-shaped extremity 18 stiifens one extremityof the band 12- and holds it in a substantially perfect circle regardless of how the remainder of the band'may be distorted to ticular tooth.

The principal purpose, however, of the bell fit over any parshaped extremity 13 isto provide a finger grip which will allow the band to be easily, positively, and accurately lifted from the tooth after the impression has set Without it being necessary to grip the band with" damaging pressure. The impresison 'compound 1d fills the band-and the bell shaped extremity 13 so as to provide axfirm'solid unit for gripping;

It will be noted that the bell shaped extremity also acts both as a funnel-like guide to direct the impression compound into the band 12 and as an enlarged seat for the" -operators thumb so that a greater pressure may be'brought to bear without danger of cutting. l

As before stated the principal objectof the invention is to provide a projection which will prevent the fingers fromslippin'g 7 maybe varied, withinthe scope of the ap- The compound within. the enlarged extremity 13 forms a key to. prevent the compound from adhering to the tooth and being drawn from the band'12:

ture.

VVILLIAM P.' LACE. 

